Update executor fixes from swarmkit

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

daemon/cluster/executor/container/container.go

@@ -276,6 +276,7 @@ func (c *containerConfig) hostConfig() *enginecontainer.HostConfig {
 		Resources: c.resources(),
 		Binds:     c.binds(),
 		Tmpfs:     c.tmpfs(),
+		GroupAdd:  c.spec().Groups,
 	}
 
 	if c.task.LogDriver != nil {

daemon/cluster/executor/container/controller.go

@@ -33,7 +33,7 @@ type controller struct {
 
 var _ exec.Controller = &controller{}
 
-// NewController returns a dockerexec runner for the provided task.
+// NewController returns a docker exec runner for the provided task.
 func newController(b executorpkg.Backend, task *api.Task) (*controller, error) {
 	adapter, err := newContainerAdapter(b, task)
 	if err != nil {